/*!	 guid.cpp
**	 Template File
**
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**	Copyright (c) 2007, 2008 Chris Moore
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
*/

#ifdef USING_PCH
#	include "pch.h"
#else
#ifdef HAVE_CONFIG_H
#	include <config.h>
#endif

#include "guid.h"
#include "quick_rng.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <ETL/stringf>
#include <functional>

#ifdef _DEBUG
#include <synfig/localization.h>
#endif

#ifdef HASH_MAP_H
#include HASH_MAP_H
#include FUNCTIONAL_H
#endif

#ifdef _WIN32
#include <windows.h>
#endif

#endif

using namespace std;
using namespace etl;
using namespace synfig;

#define MANUAL_GUID_CALC

#define GUID_RNG quick_rng
// #define GUID_RNG subtractive_rng

#ifdef MANUAL_GUID_CALC
#include <time.h>
static GUID_RNG _a, _b;
static void _set_up_rand_long_long(uint64_t &x);
static void _get_rand_long_long(uint64_t &x);
static void (*get_rand_long_long)(uint64_t&) = _set_up_rand_long_long;
static void _set_up_rand_long_long(uint64_t &x)
{
#ifdef _DEBUG
#endif
    _a = GUID_RNG(time(0) + clock());
    _b = GUID_RNG(clock());
    get_rand_long_long = _get_rand_long_long;
    _get_rand_long_long(x);
}

static void _get_rand_long_long(uint64_t &x)
{
    unsigned short* data(reinterpret_cast<unsigned short *>(&x));
    data[0] = _a(65536);
    data[1] = _a(65536);
    data[2] = _a(65536);
    data[3] = _a(65536);
}

#else
// Use OS-Dependent method

#ifdef _WIN32
// Win32
static void get_rand_long_long(uint64_t &x)
{
    _GUID* guid(reinterpret_cast<_GUID*>(&x));
    CoCreateGuid(guid);
}

#else
// Unix
static int rand_fd;
static void _set_up_rand_long_long(uint64_t &x);
static void _get_rand_long_long(uint64_t &x);
static void (*get_rand_long_long)(uint64_t&) = _set_up_rand_long_long;
static void _set_up_rand_long_long(uint64_t &x)
{
#ifdef _DEBUG
#endif
    rand_fd = open("/dev/urandom", O_RDONLY);
    get_rand_long_long = _get_rand_long_long;
    _get_rand_long_long(x);
}

static void _get_rand_long_long(uint64_t &x)
{
    read(rand_fd, &x, sizeof(x));
}

#endif
#endif

void
synfig::GUID::make_unique()
{
    get_rand_long_long(data.u_64.a);
    get_rand_long_long(data.u_64.b);
}

synfig::GUID
synfig::GUID::hasher(const String& str)
{
#ifdef HASH_MAP_H
    /* http:// www.open-std.org/jtc1/sc22/wg21/docs/papers/2003/n1456.html says:
     *
     *   "Some earlier hash table implementations gave char* special
     *    treatment: it specialized the default hash function to look
     *    at character array being pointed to, rather than the pointer
     *    itself. This proposal removes that special treatment."
     *
     * Unfortunately, the older implementation doesn't seem to want to
     * accept Strings, so we're left with this conditional compilation.
     */
# ifdef FUNCTIONAL_HASH_ON_STRING
    HASH_MAP_NAMESPACE::hash<String> string_hash_;
    const unsigned int seed(string_hash_(str));
# else  // FUNCTIONAL_HASH_ON_STRING
    HASH_MAP_NAMESPACE::hash<const char*> string_hash_;
    const unsigned int seed(string_hash_(str.c_str()));
# endif  // FUNCTIONAL_HASH_ON_STRING
#else  // HASH_MAP_H
    unsigned int seed(0x3B642879);

    for (unsigned int i = 0; i < str.size(); i++) {
        seed ^= (seed * str[i]) * i;
        seed = (seed >> (32 - (i % 24))) ^ (seed << (i % 24));
    }

#endif  // HASH_MAP_H

    GUID_RNG random(seed);
    GUID ret(0);
    ret.data.u_32.a = random(~(unsigned int)0);
    ret.data.u_32.b = random(~(unsigned int)0);
    ret.data.u_32.c = random(~(unsigned int)0);
    ret.data.u_32.d = random(~(unsigned int)0);
    return ret;
}

synfig::GUID
synfig::GUID::hasher(int i)
{
    GUID ret(0);
    GUID_RNG random(i);
    ret.data.u_32.a = random(~(unsigned int)0);
    ret.data.u_32.b = random(~(unsigned int)0);
    ret.data.u_32.c = random(~(unsigned int)0);
    ret.data.u_32.d = random(~(unsigned int)0);
    return ret;
}

synfig::GUID
synfig::GUID::hasher(const GUID &x)
{
    GUID ret(0);
    ret.data.u_32.a = GUID_RNG(x.data.u_32.d)(~(unsigned int)0);
    ret.data.u_32.b = GUID_RNG(x.data.u_32.a)(~(unsigned int)0);
    ret.data.u_32.c = GUID_RNG(x.data.u_32.b)(~(unsigned int)0);
    ret.data.u_32.d = GUID_RNG(x.data.u_32.c)(~(unsigned int)0);
    return ret;
}

String
synfig::GUID::get_string()const
{
    return strprintf("%08X%08X%08X%08X", data.u_32.a, data.u_32.b, data.u_32.c, data.u_32.d);
}

synfig::GUID::GUID(const String &str)
{
    strscanf(str, "%08X%08X%08X%08X", &data.u_32.a, &data.u_32.b, &data.u_32.c, &data.u_32.d);
}